Clostridium difficile infection (CDI) involves a range of clinical presentations including mild to self-limiting diarrhea to life-threatening pseudomembranous colitis and megacolon. Many healthy persons (e.g., infants) carry Clostridium difficile (C. difficile), and many patients become asymptomatic carriers after admission to the hospital. Most cases are diagnosed based on clinical evaluations, history of antibiotic use, and the presence of the organism and/or toxins A & B (i.e., TcdA and TcdB, respectively) in the stool. Enzyme-linked immunoassay (EIA) tests are the most frequently used test format for measuring toxin in the stool specimens, with tissue culture combined with specific neutralization being the gold standard for detecting stool toxin. More recently, polymerase chain reaction (PCR) tests are available for determining the presence of C. difficile toxin A and B genes (tcdA and tcdB) and these are used as standalone tests and in combination with the detection of glutamate dehydrogenase (GDH) for ruling out C. difficile-negative patients. All of these assays are suitable for detecting the presence of C. difficile as an aid to diagnosis but do not provide information about the severity of disease.
The severity of the disease is an important factor to recommending a proper course of treatment. In general, patients with C. difficile disease often present with fever, have slightly raised white blood cells (leukocytosis) and experience mild abdominal pain. Mild cases respond well to stopping the inciting antibiotic while moderate and/or moderate-to-severe C. difficile disease cases often require antibiotic intervention. Currently, no single lab parameter is routinely used to stratify patients based on severity of CDAD for optimizing medical and/or surgical treatment.